title: [Value of perfusion MRI in the study of pilocytic astrocytoma and hemangioblastoma: preliminary findings].
abstract: OBJECTIVE
  Pilocytic astrocytomas (PA) and hemangioblastomas (HB) can present the same morphological characteristics on conventional MRI sequences, most usually in the form of a cerebellar cystic mass with a mural nodule that strongly enhances on post-contrast T1 images. We discuss here the value of perfusion MRI in the differentiation of these two tumors, the diagnoses of which have already been histopathologically established.
  
  
  METHODS
  Eleven patients with PA and eight with HB underwent first-pass perfusion MRI. The maximum relative cerebral blood volume (rCBV(max)), defined as the ratio between the CBV(max) in tumor tissue and the CBV in healthy, contralateral white matter, is considered to be indicative of the type of tumor.
  
  
  RESULTS
  The difference between the rCBV(max) of PA (rCBV(max)=1.19+/-0.71, range 0.6-3.27) compared with that of HB (rCBV(max)=9.37+/-2.37, range 5.38-13) was significant (P<0.001). The first-pass curve crossed the baseline, corresponding to vascular permeability problems in both PA and HB.
  
  
  CONCLUSIONS
  The first-pass method of perfusion MRI is a quick and useful way to differentiate between PA and HB.
authors.affiliation: Clinique universitaire de neuroradiologie et d'IRM, Michallon, 38043 Grenoble cedex 09, France. fbing@chu-grenoble.fr
authors.forename: F
authors.initials: F
authors.lastname: Bing
authors.forename: S
authors.initials: S
authors.lastname: Kremer
authors.forename: L
authors.initials: L
authors.lastname: Lamalle
authors.forename: S
authors.initials: S
authors.lastname: Chabardes
authors.forename: A
authors.initials: A
authors.lastname: Ashraf
authors.forename: B
authors.initials: B
authors.lastname: Pasquier
authors.forename: J-F
authors.initials: JF
authors.lastname: Le Bas
authors.forename: A
authors.initials: A
authors.lastname: Krainik
authors.forename: S
authors.initials: S
authors.lastname: Grand
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000098:blood supply / Q000175:diagnosis*; D001810:Blood Volume; D001921:Brain / Q000098:blood supply* / Q000473:pathology; D001932:Brain Neoplasms / Q000098:blood supply / Q000175:diagnosis*; D002560:Cerebrovascular Circulation; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D018325:Hemangioblastoma / Q000098:blood supply / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055815:Young Adult